[instrumentation] Generalize instrumentation to be used beyond the core layer

third_party/WebKit/Source/platform/instrumentation/PlatformTraceEventsAgent.cpp

+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "platform/instrumentation/PlatformTraceEventsAgent.h"
+
+#include "platform/instrumentation/PlatformInstrumentation.h"
+#include "platform/instrumentation/tracing/TraceEvent.h"
+#include "platform/instrumentation/tracing/TracedValue.h"
+
+namespace blink {
+
+namespace {
+
+std::unique_ptr<TracedValue> buildData(
+    const probe::PlatformSendRequest& probe) {
+  std::unique_ptr<TracedValue> value = TracedValue::create();
+  value->setString("id", String::number(probe.identifier));
+  return value;
+}
+
+}  // namespace
+
+void PlatformTraceEventsAgent::will(const probe::PlatformSendRequest& probe) {
+  TRACE_EVENT_BEGIN1("devtools.timeline", "PlatformResourceSendRequest", "data",
+                     buildData(probe));
+}
+
+void PlatformTraceEventsAgent::did(const probe::PlatformSendRequest& probe) {
+  TRACE_EVENT_END0("devtools.timeline", "PlatformResourceSendRequest");
+}
+
+}  // namespace blink